Secondary battery devices used in electric motor apparatuses such as hybrid vehicles or electric vehicles need to have high power and cope with frequent output changes. As such a secondary battery device, a battery module in which a plurality of batteries are accommodated in a housing can be used. The plurality of batteries are electrically connected in series or parallel in the housing depending on required power or capacity.
On the other hand, since the battery module contains the plurality of batteries, the weight is large. Thus, when the battery module is lifted to be installed in an electric motor apparatus by human power, the work takes time.
Therefore, using a machine such as manipulator for adsorbing and lifting the battery module using a vacuum pad can be considered. However, since a cover with low strength is attached to an upper surface in the battery module, there is a concern that the cover is damaged or disconnected due to the weight of the battery module itself when the cover is adsorbed by the vacuum pad and lifted. In addition, since holes that are used to fix the cover or the like are formed on the cover of the battery module, a region available for vacuum adsorption is small. Therefore, it is difficult to reliably transport the battery module through the adsorption using the vacuum pad.